When a Web Extension had the all-urls permission and made a fetch request with a mode set to 'same-origin', it was possible for the Web Extension to read local files. This vulnerability affects Firefox < 74.
{ "binaries": [ { "binary_name": "firefox", "binary_version": "74.0+build3-0ubuntu0.16.04.1" }, { "binary_name": "firefox-dev", "binary_version": "74.0+build3-0ubuntu0.16.04.1" }, { "binary_name": "firefox-geckodriver", "binary_version": "74.0+build3-0ubuntu0.16.04.1" }, { "binary_name": "firefox-mozsymbols", "binary_version": "74.0+build3-0ubuntu0.16.04.1" } ], "availability": "No subscription required" }
{ "binaries": [ { "binary_name": "firefox", "binary_version": "74.0+build3-0ubuntu0.18.04.1" }, { "binary_name": "firefox-dev", "binary_version": "74.0+build3-0ubuntu0.18.04.1" }, { "binary_name": "firefox-geckodriver", "binary_version": "74.0+build3-0ubuntu0.18.04.1" }, { "binary_name": "firefox-mozsymbols", "binary_version": "74.0+build3-0ubuntu0.18.04.1" } ], "availability": "No subscription required" }
{ "binaries": [ { "binary_name": "firefox", "binary_version": "74.0+build3-0ubuntu1" }, { "binary_name": "firefox-dev", "binary_version": "74.0+build3-0ubuntu1" }, { "binary_name": "firefox-geckodriver", "binary_version": "74.0+build3-0ubuntu1" }, { "binary_name": "firefox-mozsymbols", "binary_version": "74.0+build3-0ubuntu1" } ], "availability": "No subscription required" }